luci-py/isolateserver.py: Add archive support when downloading.

client/isolateserver.py

 #!/usr/bin/env python
 # Copyright 2013 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
 """Archives a set of files or directories to an Isolate Server."""
 
 __version__ = '0.4.9'
 
 import base64
 import functools
 import errno
 import logging
 import optparse
 import os
 import re
+import stat
 import signal
 import sys
 import tempfile
 import threading
 import time
 import types
 import zlib
 
+import cStringIO as StringIO
+
 from third_party import colorama
 from third_party.depot_tools import fix_encoding
 from third_party.depot_tools import subcommand
 
+from libs import arfile
 from utils import file_path
 from utils import fs
 from utils import logging_utils
 from utils import lru
 from utils import net
 from utils import on_error
 from utils import subprocess42
 from utils import threading_utils
 from utils import tools
 
@@ skipping 103 matching lines @@
   """
   file_path.ensure_tree(os.path.dirname(path))
   total = 0
   with fs.open(path, 'wb') as f:
     for d in content_generator:
       total += len(d)
       f.write(d)
   return total
 
 
+def fileobj_path(fileobj):

[M-A Ruel, 2016/06/21 13:31:09]

add docstring to these 3 functions

[mithro, 2016/06/22 12:03:11]

Done.

+  name = getattr(fileobj, 'name', None)
+  if name is None:
+    return
+
+  if not isinstance(name, unicode):

[M-A Ruel, 2016/06/21 13:31:08]

Please return unicode paths instead of encoded str instances. Only linux/bsd
gets this wrong, other sane OSes (Windows, OSX) use unicode internally.

Basically, none of these scripts work with paths that are not representable as
unicode characters.

[mithro, 2016/06/22 12:03:10]

This is *creating* a unicode value from a byte (str) representation. This is
needed if someone did open('blah.txt') - such as the standard library when
creating a NamedTemporaryFile.

I've added a comment explain this.

[M-A Ruel, 2016/06/22 17:17:49]

Err, I had misread, sorry.

[mithro, 2016/06/23 07:17:21]

Acknowledged.

+    name = name.decode(sys.getfilesystemencoding())
+
+  if fs.exists(name):

[M-A Ruel, 2016/06/21 13:31:09]

why check for existence?

[mithro, 2016/06/22 12:03:10]

There are many reasons why a fileobj has a name which isn't available on the
file system any more. I want the result of this function to be passable to open.

One example is that it is reasonably common to open a file and then delete the
filename (preventing other people from opening it). In this case the fileobj
will then have a path which is no longer present on the file system.

[M-A Ruel, 2016/06/22 17:17:49]

Oh I agree in the general case, but this is not general code here and this is a
hot code path. I don't think this should be supported.

+    return name
+
+
+def fileobj_copy(dstfileobj, srcfileobj, amount=-1):

[M-A Ruel, 2016/06/21 13:31:09]

s/amount/size/ ?

[mithro, 2016/06/22 12:03:11]

Done.

+  written = 0
+  while written != amount:
+    readsize = NET_IO_FILE_CHUNK
+    if amount > 0:
+      readsize = min(readsize, amount-written)
+    data = srcfileobj.read(readsize)
+    if not data:
+      if amount == -1:
+        break
+      raise IOError('partial file, got %s, wanted %s' % (written, amount))
+    dstfileobj.write(data)
+    written += len(data)
+
+
+def putfile(srcfileobj, dstpath, file_mode=None, limit=-1):
+  srcpath = fileobj_path(srcfileobj)
+  if srcpath:
+    readonly = file_mode is None or (
+        file_mode & (stat.S_IWUSR | stat.S_IWGRP | stat.S_IWOTH))
+    if readonly:
+      # We can link the file
+      file_path.link_file(dstpath, srcpath, file_path.HARDLINK_WITH_FALLBACK)
+    else:
+      # We must copy the file
+      file_path.link_file(dstpath, srcpath, file_path.COPY)
+  else:
+    # Need to write out the file
+    with fs.open(dstpath, 'wb') as dstfileobj:
+      fileobj_copy(dstfileobj, srcfileobj, limit)
+
+  srcfileobj.close()

[M-A Ruel, 2016/06/21 13:31:08]

that shouldn't be done here.

[nodir, 2016/06/21 22:20:05]

+1

[mithro, 2016/06/22 12:03:10]

Done.

[mithro, 2016/06/22 12:03:11]

Done.

+
+  # file_mode of 0 is actually valid, so need explicit check.
+  if file_mode is not None:
+    fs.chmod(dstpath, file_mode)
+
+
 def zip_compress(content_generator, level=7):
   """Reads chunks from |content_generator| and yields zip compressed chunks."""
   compressor = zlib.compressobj(level)
   for chunk in content_generator:
     compressed = compressor.compress(chunk)
     if compressed:
       yield compressed
   tail = compressor.flush(zlib.Z_FINISH)
   if tail:
     yield tail
@@ skipping 1054 matching lines @@
   """
   cache_dir = None
 
   def __init__(self):
     self._lock = threading_utils.LockWithAssert()
     # Profiling values.
     self._added = []
     self._initial_number_items = 0
     self._initial_size = 0
     self._evicted = []
-    self._linked = []
+    self._used = []
 
   def __contains__(self, digest):
     raise NotImplementedError()
 
   def __enter__(self):
     """Context manager interface."""
     return self
 
   def __exit__(self, _exc_type, _exec_value, _traceback):
     """Context manager interface."""
     return False
 
   @property
   def added(self):
     return self._added[:]
 
   @property
   def evicted(self):
     return self._evicted[:]
 
   @property
+  def used(self):
+    return self._used[:]
+
+  @property
   def initial_number_items(self):
     return self._initial_number_items
 
   @property
   def initial_size(self):
     return self._initial_size
 
-  @property
-  def linked(self):
-    return self._linked[:]
-
   def cached_set(self):
     """Returns a set of all cached digests (always a new object)."""
     raise NotImplementedError()
 
   def cleanup(self):
     """Deletes any corrupted item from the cache and trims it if necessary."""
     raise NotImplementedError()
 
   def touch(self, digest, size):
     """Ensures item is not corrupted and updates its LRU position.
 
     Arguments:
       digest: hash digest of item to check.
       size: expected size of this item.
 
     Returns:
       True if item is in cache and not corrupted.
     """
     raise NotImplementedError()
 
   def evict(self, digest):
     """Removes item from cache if it's there."""
     raise NotImplementedError()
 
-  def read(self, digest):
-    """Returns contents of the cached item as a single str."""
+  def getfileobj(self, digest):
+    """Returns a readable file like object.
+
+    If file exists on the file system it will have a .name attribute with an
+    absolute path to the file.
+    """
     raise NotImplementedError()
 
   def write(self, digest, content):
     """Reads data from |content| generator and stores it in cache.
 
     Returns digest to simplify chaining.
     """
     raise NotImplementedError()
 
-  def hardlink(self, digest, dest, file_mode):
-    """Ensures file at |dest| has same content as cached |digest|.
-
-    If file_mode is provided, it is used to set the executable bit if
-    applicable.
-    """
-    raise NotImplementedError()
-
 
 class MemoryCache(LocalCache):
   """LocalCache implementation that stores everything in memory."""
 
   def __init__(self, file_mode_mask=0500):
     """Args:
       file_mode_mask: bit mask to AND file mode with. Default value will make
           all mapped files to be read only.
     """
     super(MemoryCache, self).__init__()
@@ skipping 14 matching lines @@
   def touch(self, digest, size):
     with self._lock:
       return digest in self._contents
 
   def evict(self, digest):
     with self._lock:
       v = self._contents.pop(digest, None)
       if v is not None:
         self._evicted.add(v)
 
-  def read(self, digest):
+  def getfileobj(self, digest):
     with self._lock:

[M-A Ruel, 2016/06/21 13:31:08]

Nesting is not optimal;

with self._lock:
  try:
    d = self._contents[digest]
  except KeyError:
    raise CacheMiss(digest)
  self._used.append(len(d))
return StringIO.StringIO(d)

it's not going to affect anything performance wise, it's more to document the
scoping.

[mithro, 2016/06/22 12:03:10]

Done.

       try:
-        return self._contents[digest]
+        d = self._contents[digest]
+        self._used.append(len(d))
+        return StringIO.StringIO(d)
       except KeyError:
         raise CacheMiss(digest)
 
   def write(self, digest, content):
     # Assemble whole stream before taking the lock.
     data = ''.join(content)
     with self._lock:
       self._contents[digest] = data
       self._added.append(len(data))
     return digest
 
-  def hardlink(self, digest, dest, file_mode):
-    """Since data is kept in memory, there is no filenode to hardlink."""
-    data = self.read(digest)
-    file_write(dest, [data])
-    if file_mode is not None:
-      fs.chmod(dest, file_mode & self._file_mode_mask)
-    with self._lock:
-      self._linked.append(len(data))
-
 
 class CachePolicies(object):
   def __init__(self, max_cache_size, min_free_space, max_items):
     """
     Arguments:
     - max_cache_size: Trim if the cache gets larger than this value. If 0, the
                       cache is effectively a leak.
     - min_free_space: Trim if disk free space becomes lower than this value. If
                       0, it unconditionally fill the disk.
     - max_items: Maximum number of items to keep in the cache. If 0, do not
@@ skipping 111 matching lines @@
       self._protected.add(digest)
     return True
 
   def evict(self, digest):
     with self._lock:
       # Do not check for 'digest in self._protected' since it could be because
       # the object is corrupted.
       self._lru.pop(digest)
       self._delete_file(digest, UNKNOWN_FILE_SIZE)
 
-  def read(self, digest):
+  def getfileobj(self, digest):
     try:
-      with fs.open(self._path(digest), 'rb') as f:
-        return f.read()
+      f = fs.open(self._path(digest), 'rb')
+      with self._lock:
+        self._used.append(self._lru[digest])
+      return f
     except IOError:
       raise CacheMiss(digest)
 
   def write(self, digest, content):
     assert content is not None
     with self._lock:
       self._protected.add(digest)
     path = self._path(digest)
     # A stale broken file may remain. It is possible for the file to have write
     # access bit removed which would cause the file_write() call to fail to open
@@ skipping 10 matching lines @@
       file_path.try_remove(path)
       raise
     # Make the file read-only in the cache.  This has a few side-effects since
     # the file node is modified, so every directory entries to this file becomes
     # read-only. It's fine here because it is a new file.
     file_path.set_read_only(path, True)
     with self._lock:
       self._add(digest, size)
     return digest
 
-  def hardlink(self, digest, dest, file_mode):
-    """Hardlinks the file to |dest|.
-
-    Note that the file permission bits are on the file node, not the directory
-    entry, so changing the access bit on any of the directory entries for the
-    file node will affect them all.
-    """
-    path = self._path(digest)
-    if not file_path.link_file(dest, path, file_path.HARDLINK_WITH_FALLBACK):
-      # Report to the server that it failed with more details. We'll want to
-      # squash them all.
-      on_error.report('Failed to hardlink\n%s -> %s' % (path, dest))
-
-    if file_mode is not None:
-      # Ignores all other bits.
-      fs.chmod(dest, file_mode & 0500)
-    with self._lock:
-      self._linked.append(self._lru[digest])
-
   def _load(self):
     """Loads state of the cache from json file."""
     self._lock.assert_locked()
 
     if not os.path.isdir(self.cache_dir):
       fs.makedirs(self.cache_dir)
     else:
       # Make sure the cache is read-only.
       # TODO(maruel): Calculate the cost and optimize the performance
       # accordingly.
@@ skipping 210 matching lines @@
       pending[h] = isolated_file
       fetch_queue.add(h, priority=threading_utils.PRIORITY_HIGH)
 
     # Start fetching root *.isolated file (single file, not the whole bundle).
     retrieve_async(self.root)
 
     while pending:
       # Wait until some *.isolated file is fetched, parse it.
       item_hash = fetch_queue.wait(pending)
       item = pending.pop(item_hash)
-      item.load(fetch_queue.cache.read(item_hash))
+      item.load(fetch_queue.cache.getfileobj(item_hash).read())

[M-A Ruel, 2016/06/21 13:31:09]

with fetch_queue.cache.getfileobj(item_hash) as f:
?

and/or change load() to accept a file object.

[mithro, 2016/06/22 12:03:10]

Done
I'll leave that for the CL which changes everything to use file like objects.

 
       # Start fetching included *.isolated files.
       for new_child in item.children:
         retrieve_async(new_child)
 
       # Always fetch *.isolated files in traversal order, waiting if necessary
       # until next to-be-processed node loads. "Waiting" is done by yielding
       # back to the outer loop, that waits until some *.isolated is loaded.
       for node in isolated_format.walk_includes(self.root):
         if node not in processed:
@@ skipping 17 matching lines @@
     """Starts fetching files from |isolated| that are not yet being fetched.
 
     Modifies self.files.
     """
     logging.debug('fetch_files(%s)', isolated.obj_hash)
     for filepath, properties in isolated.data.get('files', {}).iteritems():
       # Root isolated has priority on the files being mapped. In particular,
       # overridden files must not be fetched.
       if filepath not in self.files:
         self.files[filepath] = properties
+
+        # Make sure if the isolated is read only, the mode doesn't have write
+        # bits.
+        if 'm' in properties and self.read_only:
+          properties['m'] &= ~(stat.S_IWUSR | stat.S_IWGRP | stat.S_IWOTH)
+
+        # Preemptively request hashed files.
         if 'h' in properties:
-          # Preemptively request files.
           logging.debug('fetching %s', filepath)
           fetch_queue.add(
               properties['h'], properties['s'], threading_utils.PRIORITY_MED)
 
   def _update_self(self, node):
     """Extracts bundle global parameters from loaded *.isolated file.
 
     Will be called with each loaded *.isolated file in order of traversal of
     isolated include graph (see isolated_format.walk_includes).
     """
@@ skipping 141 matching lines @@
       logging.info('Retrieving remaining files (%d of them)...',
           fetch_queue.pending_count)
       last_update = time.time()
       with threading_utils.DeadlockDetector(DEADLOCK_TIMEOUT) as detector:
         while remaining:
           detector.ping()
 
           # Wait for any item to finish fetching to cache.
           digest = fetch_queue.wait(remaining)
 
-          # Link corresponding files to a fetched item in cache.
+          # Create the files in the destination using item in cache as the
+          # source.
           for filepath, props in remaining.pop(digest):
-            dest = os.path.join(outdir, filepath)
-            if os.path.exists(dest):
-              raise AlreadyExists('File %s already exists' % dest)
-            cache.hardlink(digest, dest, props.get('m'))
+            fullpath = os.path.join(outdir, filepath)
+            srcfileobj = cache.getfileobj(digest)

[M-A Ruel, 2016/06/21 13:31:08]

with cache.getfileobj(digest) as f:

[mithro, 2016/06/22 12:03:10]

Done.

+
+            isarchive = props.get('a')
+            if isarchive:
+              basedir = os.path.dirname(fullpath)
+
+              if isarchive == 'ar':
+                extractor = arfile.ArFileReader(srcfileobj, fullparse=False)
+              else:
+                raise isolated_format.IsolatedError(
+                    'Unknown archive format %r', isarchive)
+
+              for ai, ifd in extractor:
+                fp = os.path.normpath(os.path.join(basedir, ai.name))
+                file_path.ensure_tree(os.path.dirname(fp))
+                putfile(ifd, fp, ai.mode, ai.size)
+
+            else:
+              file_mode = props.get('m')
+              if file_mode:
+                # Ignore all bits apart from the user
+                file_mode &= 0700
+              putfile(srcfileobj, fullpath, file_mode)
 
           # Report progress.
           duration = time.time() - last_update
           if duration > DELAY_BETWEEN_UPDATES_IN_SECS:
             msg = '%d files remaining...' % len(remaining)
             print msg
             logging.info(msg)
             last_update = time.time()
 
   # Cache could evict some items we just tried to fetch, it's a fatal error.
@@ skipping 316 matching lines @@
   dispatcher = subcommand.CommandDispatcher(__name__)
   return dispatcher.execute(OptionParserIsolateServer(), args)
 
 
 if __name__ == '__main__':
   subprocess42.inhibit_os_error_reporting()
   fix_encoding.fix_encoding()
   tools.disable_buffering()
   colorama.init()
   sys.exit(main(sys.argv[1:]))